I lived in Poland for 11 years and my wife comes from Bartoszyce, the last town before the Kalingrad border. I've ridden up to have a look when staying with the in-laws (at the border and also the old roads that no longer cross where the border disects what were once joined up communities) but have not crossed over since I've never had the time.
It is, partly for the above reasons, a place I'd love to go and will one day.
My advice as someone who went round most of the region in the wild days of the early 1990s would be to ignore the prophets of doom, put up with the likely border delays and go for it. Chances are you'll see things that the average tourist hasn't yet.
My understanding is that recently they've started to open up so now is the time.
As in most of the region (including Poland) try and find secure parking if you stay the night (tip: you can often negotiate to park in the secure parking of a well-guarded swanky hotel even if you don't stay there).
PM me if you want anything else, including places to take in en route (Malbork, Grunwald, Treblinka are kind of on the way down to Warsaw and there are some less obvious things to see as well)
PS Check out the section on Speeding in Poland on
www.roadmc.com OK, I contributed it ....
Cheers
Andy